London Irish always like to throw a spectacular St Patrick's Day bash, albeit a late one, and they led Sale a merry dance in front of a well‑lubricated audience today. Fast, furious and full of vigour, Irish played as if someone had flicked a switch and re-energised the sluggish, injury-hit side which had won once in nine attempts since the beginning of the year. It is amazing what a firmer surface, a three-week break and a warm-weather training camp in Lanzarote can do for you.

It also served to remind those who have spent the last two months watching England what a little bit of ambition can achieve. Poor old Sale were not so much beaten up as pierced beyond repair and were lucky, as they say, to get nil. Even if there was an element of saving their best for the looming Friday-night dog-fight with their fellow relegation contenders Worcester, this was another grievous blow to the Sharks' collective self-confidence. "We know we're playing for our lives on Friday night," said Kingsley Jones, Sale's ever honest director of rugby.

Irish, in contrast, are back into the top four and will stay there if they continue at this sort of Pogues-like lick. They scored five tries and could have had at least a couple more against a side containing six international backs, the majority of them British and Irish Lions. Unfortunately Sale do not have that kind of pedigree up front and also opted to leave seven forwards behind in Manchester in preparation for the Worcester game.

Jones did briefly consider fielding a complete reserve team, which would have got him into serious hot water but, with hindsight, might have been the wiser option. Injuries to Carl Fearns (knee), Luke Abraham (shoulder) and Dwayne Peel (shoulder) threaten their participation in the closing weeks of the regular season when Sale, who currently have a two-point advantage over the bottom-placed Warriors, will need all their available infantry.

Out in the Canaries, Irish's head coach, Toby Booth, decided to "review the core principles of how we play" and the old familiar weapons – quick ball, cute offloads and slick distribution – were all back in the armoury. So, too, was their England flanker Steffon Armitage who once again played like a man with numerous points to prove and has now scored five tries in his last four games. "The only thing I can think of is that he doesn't fit what England are trying to do," shrugged Booth, as convinced as ever that Armitage possesses all the attributes to be an international No7. If Armitage is not the answer, you have to wonder about those asking the question.

Booth also went out of his way to praise Ryan Lamb's decision-making, conscious of the need to burnish his playmaker's confidence with the season-defining play-offs looming. With Saracens winning well and Bath staging a grandstand finish, yesterday's bonus point was important and the Easter Sunday showdown with Wasps at Adams Park will be another critical encounter. "Hopefully this'll be the start of a resurgence," said Booth, conscious that harder, drier conditions suit his strolling players appreciably better than the mudheaps of winter. "We're not in this competition to make up the numbers."

The first half, though, was less about arithmetic than Scrabble-inspired symmetry. All Irish's first-half points were scored by men with an equal number of letters in their first names and surnames, John Rudd and Lamb leaving the Sharks management to mutter only four-letter oaths. Rudd's sixth-minute try was notable for the crispness of the build-up play and a timely wardrobe malfunction, Lamb's shirt ripping as a desperate defender vainly tried to stop his sharp break. Had Delon Armitage, sprightly on the wing, not had a try ruled out for a fractional forward pass, Sale could have been finished by the interval.

As it was they turned around 14-0 down to face a renewed onslaught. The rampaging Chris Hala'ufia made space down the short side for Steffon Armitage to demonstrate his pace and power and the same combination combined from a close-range scrum to send the flanker surging over. The purposeful Pete Hewat secured the bonus point from Alex Corbisiero's pass and the replacement prop, another English-qualified player with a big future, added a well-received try of his own.

This was Irish's biggest crowd of the season and one suspects a lot of them will be back. The suffering Jones, who hitched a ride home on club owner Brian Kennedy's private plane, now needs a seriously good Friday.